1 files changed, 242 insertions, 0 deletions
diff --git a/drivers/nvme/target/discovery.c b/drivers/nvme/target/discovery.c
new file mode 100644
index 000000000..eae29f493
--- /dev/null
+++ b/drivers/nvme/target/discovery.c
@@ -0,0 +1,242 @@
+/*
+ * Discovery service for the NVMe over Fabrics target.
+ * Copyright (C) 2016 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/slab.h>
+#include <generated/utsrelease.h>
+#include "nvmet.h"
+
+struct nvmet_subsys *nvmet_disc_subsys;
+
+u64 nvmet_genctr;
+
+void nvmet_referral_enable(struct nvmet_port *parent, struct nvmet_port *port)
+{
+	down_write(&nvmet_config_sem);
+	if (list_empty(&port->entry)) {
+		list_add_tail(&port->entry, &parent->referrals);
+		port->enabled = true;
+		nvmet_genctr++;
+	}
+	up_write(&nvmet_config_sem);
+}
+
+void nvmet_referral_disable(struct nvmet_port *port)
+{
+	down_write(&nvmet_config_sem);
+	if (!list_empty(&port->entry)) {
+		port->enabled = false;
+		list_del_init(&port->entry);
+		nvmet_genctr++;
+	}
+	up_write(&nvmet_config_sem);
+}
+
+static void nvmet_format_discovery_entry(struct nvmf_disc_rsp_page_hdr *hdr,
+		struct nvmet_port *port, char *subsys_nqn, char *traddr,
+		u8 type, u32 numrec)
+{
+	struct nvmf_disc_rsp_page_entry *e = &hdr->entries[numrec];
+
+	e->trtype = port->disc_addr.trtype;
+	e->adrfam = port->disc_addr.adrfam;
+	e->treq = port->disc_addr.treq;
+	e->portid = port->disc_addr.portid;
+	/* we support only dynamic controllers */
+	e->cntlid = cpu_to_le16(NVME_CNTLID_DYNAMIC);
+	e->asqsz = cpu_to_le16(NVME_AQ_DEPTH);
+	e->subtype = type;
+	memcpy(e->trsvcid, port->disc_addr.trsvcid, NVMF_TRSVCID_SIZE);
+	memcpy(e->traddr, traddr, NVMF_TRADDR_SIZE);
+	memcpy(e->tsas.common, port->disc_addr.tsas.common, NVMF_TSAS_SIZE);
+	strncpy(e->subnqn, subsys_nqn, NVMF_NQN_SIZE);
+}
+
+/*
+ * nvmet_set_disc_traddr - set a correct discovery log entry traddr
+ *
+ * IP based transports (e.g RDMA) can listen on "any" ipv4/ipv6 addresses
+ * (INADDR_ANY or IN6ADDR_ANY_INIT). The discovery log page traddr reply
+ * must not contain that "any" IP address. If the transport implements
+ * .disc_traddr, use it. this callback will set the discovery traddr
+ * from the req->port address in case the port in question listens
+ * "any" IP address.
+ */
+static void nvmet_set_disc_traddr(struct nvmet_req *req, struct nvmet_port *port,
+		char *traddr)
+{
+	if (req->ops->disc_traddr)
+		req->ops->disc_traddr(req, port, traddr);
+	else
+		memcpy(traddr, port->disc_addr.traddr, NVMF_TRADDR_SIZE);
+}
+
+static void nvmet_execute_get_disc_log_page(struct nvmet_req *req)
+{
+	const int entry_size = sizeof(struct nvmf_disc_rsp_page_entry);
+	struct nvmet_ctrl *ctrl = req->sq->ctrl;
+	struct nvmf_disc_rsp_page_hdr *hdr;
+	size_t data_len = nvmet_get_log_page_len(req->cmd);
+	size_t alloc_len = max(data_len, sizeof(*hdr));
+	int residual_len = data_len - sizeof(*hdr);
+	struct nvmet_subsys_link *p;
+	struct nvmet_port *r;
+	u32 numrec = 0;
+	u16 status = 0;
+
+	/*
+	 * Make sure we're passing at least a buffer of response header size.
+	 * If host provided data len is less than the header size, only the
+	 * number of bytes requested by host will be sent to host.
+	 */
+	hdr = kzalloc(alloc_len, GFP_KERNEL);
+	if (!hdr) {
+		status = NVME_SC_INTERNAL;
+		goto out;
+	}
+
+	down_read(&nvmet_config_sem);
+	list_for_each_entry(p, &req->port->subsystems, entry) {
+		if (!nvmet_host_allowed(req, p->subsys, ctrl->hostnqn))
+			continue;
+		if (residual_len >= entry_size) {
+			char traddr[NVMF_TRADDR_SIZE];
+
+			nvmet_set_disc_traddr(req, req->port, traddr);
+			nvmet_format_discovery_entry(hdr, req->port,
+					p->subsys->subsysnqn, traddr,
+					NVME_NQN_NVME, numrec);
+			residual_len -= entry_size;
+		}
+		numrec++;
+	}
+
+	list_for_each_entry(r, &req->port->referrals, entry) {
+		if (residual_len >= entry_size) {
+			nvmet_format_discovery_entry(hdr, r,
+					NVME_DISC_SUBSYS_NAME,
+					r->disc_addr.traddr,
+					NVME_NQN_DISC, numrec);
+			residual_len -= entry_size;
+		}
+		numrec++;
+	}
+
+	hdr->genctr = cpu_to_le64(nvmet_genctr);
+	hdr->numrec = cpu_to_le64(numrec);
+	hdr->recfmt = cpu_to_le16(0);
+
+	up_read(&nvmet_config_sem);
+
+	status = nvmet_copy_to_sgl(req, 0, hdr, data_len);
+	kfree(hdr);
+out:
+	nvmet_req_complete(req, status);
+}
+
+static void nvmet_execute_identify_disc_ctrl(struct nvmet_req *req)
+{
+	struct nvmet_ctrl *ctrl = req->sq->ctrl;
+	struct nvme_id_ctrl *id;
+	u16 status = 0;
+
+	id = kzalloc(sizeof(*id), GFP_KERNEL);
+	if (!id) {
+		status = NVME_SC_INTERNAL;
+		goto out;
+	}
+
+	memset(id->fr, ' ', sizeof(id->fr));
+	strncpy((char *)id->fr, UTS_RELEASE, sizeof(id->fr));
+
+	/* no limit on data transfer sizes for now */
+	id->mdts = 0;
+	id->cntlid = cpu_to_le16(ctrl->cntlid);
+	id->ver = cpu_to_le32(ctrl->subsys->ver);
+	id->lpa = (1 << 2);
+
+	/* no enforcement soft-limit for maxcmd - pick arbitrary high value */
+	id->maxcmd = cpu_to_le16(NVMET_MAX_CMD);
+
+	id->sgls = cpu_to_le32(1 << 0);	/* we always support SGLs */
+	if (ctrl->ops->has_keyed_sgls)
+		id->sgls |= cpu_to_le32(1 << 2);
+	if (req->port->inline_data_size)
+		id->sgls |= cpu_to_le32(1 << 20);
+
+	strcpy(id->subnqn, ctrl->subsys->subsysnqn);
+
+	status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));
+
+	kfree(id);
+out:
+	nvmet_req_complete(req, status);
+}
+
+u16 nvmet_parse_discovery_cmd(struct nvmet_req *req)
+{
+	struct nvme_command *cmd = req->cmd;
+
+	if (unlikely(!(req->sq->ctrl->csts & NVME_CSTS_RDY))) {
+		pr_err("got cmd %d while not ready\n",
+		       cmd->common.opcode);
+		return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
+	}
+
+	switch (cmd->common.opcode) {
+	case nvme_admin_get_log_page:
+		req->data_len = nvmet_get_log_page_len(cmd);
+
+		switch (cmd->get_log_page.lid) {
+		case NVME_LOG_DISC:
+			req->execute = nvmet_execute_get_disc_log_page;
+			return 0;
+		default:
+			pr_err("unsupported get_log_page lid %d\n",
+			       cmd->get_log_page.lid);
+		return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
+		}
+	case nvme_admin_identify:
+		req->data_len = NVME_IDENTIFY_DATA_SIZE;
+		switch (cmd->identify.cns) {
+		case NVME_ID_CNS_CTRL:
+			req->execute =
+				nvmet_execute_identify_disc_ctrl;
+			return 0;
+		default:
+			pr_err("unsupported identify cns %d\n",
+			       cmd->identify.cns);
+			return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
+		}
+	default:
+		pr_err("unsupported cmd %d\n", cmd->common.opcode);
+		return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
+	}
+
+	pr_err("unhandled cmd %d\n", cmd->common.opcode);
+	return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
+}
+
+int __init nvmet_init_discovery(void)
+{
+	nvmet_disc_subsys =
+		nvmet_subsys_alloc(NVME_DISC_SUBSYS_NAME, NVME_NQN_DISC);
+	if (!nvmet_disc_subsys)
+		return -ENOMEM;
+	return 0;
+}
+
+void nvmet_exit_discovery(void)
+{
+	nvmet_subsys_put(nvmet_disc_subsys);
+}